Stage and method of manufacturing stage

This application is a U.S. continuation application filed under 35 U.S.C. § 111(a), of International Application No. PCT/JP2020/007433, filed on Feb. 25, 2020, which claims priority to Japanese Patent Application No. 2019-037589, filed on Mar. 1, 2019, the disclosures of which are incorporated herein by reference.

An embodiment of the present invention relates to a stage and a method of manufacturing the stage, for example, a stage for placing a substrate and a method of manufacturing the stage for placing the substrate.

Semiconductor devices are installed in almost all electronic devices and play an important role for the functions of the electronic devices. Semiconductor devices utilize semiconductor characteristics possessed by silicon, etc. Semiconductor devices are constructed by stacking a semiconductor film, an insulating film, and a conductive film on a substrate and patterning these films. These films are stacked by vapor deposition, sputtering, chemical vapor phase deposition (CVD), or substrate chemical reactions, and are patterned by a photolithography process. The photolithography process includes the formation of a resist on the films that are subjected to patterning, the exposure of the resist, the formation of a resist mask by development, the partial removal of these films by etching, and the removal of the resist mask.

The characteristics of the films described above depend largely on the conditions for forming the films or the conditions for patterning. One of the above conditions is a voltage applied to a mounting table (hereinafter referred to as stage) for installing a substrate. For example, the voltage applied to the stage included in an etching device has been increasing with the miniaturization of recent semiconductor devices, since the ratio of the diameter of a hole to be processed and the thickness of the film to be processed is increased. As the voltage applied to the stage increases, withstand voltages of members included in the stage need to be improved. The members included in the stage may be, for example, a cooling plate and an electrostatic chuck, or the like. For example, Japanese Patent No. 6027407 and Japanese Registered Utility Model No. 2600558 disclose a stage in which an insulating film is formed on the surface by using a thermal spraying method to improve the withstand voltage.

One embodiment of the present invention is a stage. The stage includes a base material having a first surface and a second surface adjacent to the first surface, and an insulating film consisting of a plurality of particles each having a flat surface. A part of the flat surface included in the insulating film is provided along the first surface and the second surface.

In another embodiment, the base material includes a third surface in a direction 180 degrees opposite to the first surface, and a part of the flat surface included in the insulating film may be provided along the third surface.

In another embodiment, a surface obtained by extending the first surface and a surface obtained by extending the second surface may be provided to intersect at 90 degrees.

In another embodiment, a ratio of an area of a void to a predetermined area of the insulating film may be 5% or less.

In another embodiment, the base material may have a flow path through which a liquid flows.

In another embodiment, an electrostatic chuck may be provided on the insulating film.

One embodiment of the present invention is a method of manufacturing a stage, the method includes spraying an insulator onto a first surface from a perpendicular direction to the first surface while moving in a parallel direction to the first surface of the base material, and spraying the insulator onto a second surface from a perpendicular direction to the second surface while moving in a parallel direction to the second surface of the base material adjacent to the first surface.

In another embodiment, the method may include spraying the insulator onto a third surface from a perpendicular direction to the third surface while moving in a parallel direction to the third surface of the base material in a direction 180 degrees opposite to the first surface.

In another embodiment, a surface obtained by extending the first surface and a surface obtained by extending the second surface may be formed to intersect at 90 degrees.

In another embodiment, the spraying of the insulator onto the first surface and the spraying of the insulator onto the second surface may be continuously performed.

In another embodiment, the spraying of the insulator onto the first surface and the spraying of the insulator onto the second surface may be alternately repeated.

In another embodiment, the spraying of the insulator onto the third surface, the spraying of the insulator onto the second surface, and the spraying of the insulator onto the first surface may be continuously performed.

In another embodiment, the flat surface of some of the particles included in the insulating film may be sprayed so as to be provided along the first surface and the second surface.

In another embodiment, the flat surface of some of the particles included in the insulating film may be sprayed so as to be provided along the third surface.

Hereinafter, embodiments of the invention disclosed in the present application will be described with reference to the drawings. However, the present invention can be implemented in various forms without departing from the gist thereof and should not be construed as being limited to the description of the following exemplary embodiments.

For the sake of clarity of description, the drawings may be schematically represented with respect to widths, thicknesses, shapes, and the like of the respective portions compared with actual embodiments. However, they are merely an example and do not limit the interpretation of the present invention. In this specification and respective drawings, components having the same functions as those described with reference to the preceding drawings are denoted by the same reference numerals, and a duplicate description thereof may be omitted.

In the present invention, when a single film is processed to form a plurality of films, this plurality of films may have different functions and roles. However, this plurality of films is derived from films formed as the same layer in the same process and has the same layer structure and the same material. Therefore, the plurality of films is defined as existing in the same layer.

In this specification and the drawings, when multiple portions of one configuration are distinguished, for example, the same reference numerals are used, and a hyphen and a natural number are used.

In a conventional thermal spraying method, for example, a method of spraying an insulating film on a stage is changed for each surface of the stage. Therefore, gaps or voids have formed in the insulating film at an interface between the surfaces of the stage (hereinafter sometimes referred to as corner portion). Then, a withstand voltage of the sprayed insulating film decreased due to the gaps or voids. Therefore, in the stage, it is a challenge to improve the withstand voltage (hereinafter sometimes referred to as dielectric breakdown voltage) of the members contained in the stage to be sprayed by reducing the gaps or voids in the insulating film sprayed using the thermal spraying method.

It is one of purposes of an embodiment of the present invention to provide a stage having a high withstand voltage and a method of manufacturing the stage.

Some of the following embodiments illustrate stages having a high withstand voltage and methods of manufacturing the stages.

In this embodiment, a stageaccording to an embodiment of the present invention will be described.

1-1. Configuration of Stage

shows a cross-sectional view of the stage. As shown in, the stagehas a support plateand a first insulating film.

The support platehas at least a first surface, a second surfaceadjacent to the first surface, and a third surface. The support platehas a first base materialand a second base material. The first base materialhas the first surfaceand the second surface, and the second base materialhas the third surface. The first insulating filmis provided on the first base materialand the second base materialby a thermal spraying method. That is, the first insulating filmis provided on the first surface, the second surface, and the third surface. The second surfacemay include all of a portion of a second surface-, a second surface-, a second surface-, and a second surface-. In an embodiment of the present invention, although an example is shown in which the first insulating filmis provided on all of the third surfaceis shown, the first insulating filmmay be provided on a part of the third surface.

A surface obtained by extending the first surfaceand a surface obtained by extending the second surface-are formed to intersect at 90 degrees or approximately 90 degrees to each other. A surface obtained by extending the second surface-and a surface obtained by extending the second surface-are formed to intersect at 90 degrees or approximately 90 degrees to each other. A surface obtained by extending the second surface-and a surface obtained by extending the second surface-are formed to intersect at 90 degrees or approximately 90 degrees to each other. A surface obtained by extending the second surface-and a surface obtained by extending the second surface-are formed to intersect at 90 degrees or approximately 90 degrees to each other. A surface obtained by extending the second surface-and a surface obtained by extending the third surfaceare formed to intersect at 90 degrees or approximately 90 degrees to each other. The first surfaceand the third surfaceare formed in a direction 180 degrees or approximately 180 degrees opposite to each other.

The main material of the first base materialand the second base materialis metal or a ceramic, and for example, titanium (Ti), aluminum (Al), stainless steel, or an oxide containing these or the like can be used. The support platemay be provided with an openingto arrange a temperature sensor on a bottom surface. A thermocouple or the like can be used for the temperature sensor. In an embodiment, although and example is shown in which the first insulating filmis provided on the inner wall of the opening, the first insulating filmmay be provided on a part of the inner wall of the opening.

A groove (flow path)may be provided in the support plateof the stagefor recirculating a medium for controlling the temperature of a substrate. A liquid medium such as water, an alcohol such as isopropanol or ethylene glycol, or silicone oil can be used as the medium. The grooveis formed in one or both of the first base materialand the second base material, and then the first base materialand the second base materialare joined by brazing or the like. The medium may be used in both cases when the stageis cooled or heated.

Using a temperature controllerillustrated in, which will be described later, the temperature of the support platecan be controlled by flowing a temperature-controlled medium through the groove.

Any known material can be used as the first insulating filmas long as it satisfies a desired withstand voltage and can be sprayed by the thermal spraying method. For example, one or more kinds of oxides of alkaline earth metal, rare earth metal, aluminum (Al), tantalum (Ta) and silicon (Si) are used as the material used for the first insulating film. Specific examples include aluminum oxide (AlO) and magnesium oxide (MgO), and the like.

The material used for the first insulating filmmay include an inorganic insulator. Specific examples of the inorganic insulator include aluminum oxide, titanium oxide, chromium oxide, zirconium oxide, magnesium oxide, yttrium oxide, or a composite oxide thereof.

The thermal spraying method used in this specification and the like may be, for example, a Rokide thermal spraying method, a plasma spraying method, or a thermal spraying method in which these methods are combined.

Optionally, the stagemay have one or more through hole(s)penetrating the support plate. A helium introduction tube may be provided in a chamberillustrated in, which will be described later, so as to allow a highly thermally conductive gas, such as helium, to flow through the through hole. This allows the gas to flow through a gap between the stageand the substrate and efficiently convey thermal energy of the stageto the substrate. In an embodiment of the present invention, although an example is shown in which the first insulating filmis provided on the inner wall of the through hole, the first insulating filmmay be provided on a part of the inner wall of the through hole.

As illustrated in, the stagemay further include an electrostatic chuckas a mechanism for securing the substrate onto the stage. The electrostatic chuckmay have a structure in which, for example, electrostatic chuck electrodesare covered with an insulating film. By applying a high voltage (several hundred V to several thousand V) to the electrostatic chuck electrodes, it is possible to fix the substrate due to a Coulomb force between a charge generated in the electrostatic chuck electrodesand a charge generated on the back surface of the substrate and having the opposite polarity to the charge generated in the electrostatic chuck electrodes. A ceramic such as aluminum oxide or aluminum nitride, and boron nitride can be used as the insulator. The insulating filmdoes not have to be completely insulated and may have some degree of conductivity (e.g., resistance ratio in the order of 10Ωcm to 10Ωcm). In this case, the above-described ceramic is doped with a metal oxide such as titanium oxide, zirconium oxide, or hafnium oxide to form the insulating film. A ribmay be provided around the electrostatic chuckto determine the position of the substrate.

1-2. Manufacture of Stage

are cross-sectional views showing a first method of manufacturing the stage. Descriptions of the same or similar structures as those of,, ormay be omitted.

The first method of manufacturing the stagewill be described with reference to. First, as shown in, the support plateis prepared.

Next, as shown in, the first insulating filmis formed on at least a part of the first surfacewhile moving a thermal sprayerincluded in the thermal spraying device in a parallel direction to the first surfaceof the support plate. At this time, the thermal sprayermay repeatedly move from an end of the support platetoward the approximate center of the first surfaceof the support plateand from the approximate center of the support platetoward the end of the support plateand the first insulating filmmay be formed on at least a part of the first surfacewhile moving in a zigzag manner. Forming the first insulating filmon the first surfaceusing the thermal sprayerincluded in the thermal spraying device may be referred to as forming the first insulating filmon the first surfaceusing the thermal spraying method. At this time, when the direction in which the particles sprayed from the thermal sprayerare sprayed onto the first surfaceis a thermal spraying direction, the thermal spraying direction and the first surfacemay be substantially perpendicular or perpendicular. Movement of the thermal sprayerin a parallel direction to the first surfacemay be in one direction, or both one direction and 180 degrees in an opposite direction, as shown in. By forming the first insulating filmon the first surfacewhile moving in both one direction and 180 degrees in an opposite direction, the first insulating filmcan be uniformly formed on the first surface.

Next, as shown in, the first insulating filmis formed on at least a part of the second surfacewhile moving the thermal sprayerin a parallel direction to the second surface. At this time, the thermal sprayermay repeatedly move from one end of the second surface(e.g., the first surfaceside) toward the other end of the second surface(e.g., the third surfaceside) and from the other end of the second surfacetoward one end of the second surface, and the first insulating filmmay be formed on at least a part of the second surfacewhile moving the thermal sprayerin a zigzag manner. Forming the first insulating filmon the second surfaceusing the thermal sprayerincluded in the thermal device may be referred to as forming the first insulating filmon the second surfaceusing the thermal spraying method. At this time, when the direction in which the particles sprayed from the thermal sprayerare sprayed onto the second surfaceis the thermal spraying direction, the thermal spraying direction and the second surfacemay be substantially perpendicular or perpendicular. Movement of the thermal sprayerin a parallel direction to the second surfacemay be in one direction, or in both one direction and 180 degrees in an opposite direction, as shown in. By forming the first insulating filmon the second surfacewhile moving the thermal sprayerin both one direction and 180 degrees in an opposite direction, the first insulating filmcan be uniformly formed on the second surface.

Next, similar to the method described in, again, the first insulating filmis formed on the first surfaceas shown in. Subsequently, similar to the method described in, again, the first insulating filmis formed on the second surfaceas shown in.

As described above, by forming the first insulating filmon each surface, the first insulating filmcan be provided on the support plateas shown in. Further, for example, as shown in, the stagecan be manufactured by joining the support plateand the electrostatic chuck. The support plateand the electrostatic chuckcan be joined, for example, by welding, screwing, or brazing. The braze used in the brazing process includes an alloy containing silver, copper, and zinc, an alloy containing copper and zinc, copper containing trace amounts of phosphorus, aluminum, and alloys thereof, an alloy containing titanium, copper, and nickel, an alloy containing titanium, zirconium, and copper, and an alloy containing titanium, zirconium, copper, and nickel, and the like.

As described above with reference to, by alternately repeating the formation of the first insulating filmon the first surfaceand the formation of the first insulating filmon the second surface, the first insulating filmcan be uniformly formed on the first surfaceand the second surfaceof the support plate. By alternately repeating the formation of the first insulating filmon the first surfaceand the formation of the first insulating filmon the second surface, it is possible to suppress the generation of a gap or void in a corner portion between the first surfaceand the second surface. The first insulating filmformed on the first surfaceand the first insulating filmformed on the second surfacemay overlap by alternately repeating the formation of the first insulating filmon the first surfaceand the formation of the first insulating filmon the second surface. By overlapping the first insulating filmformed on the first surfaceand the first insulating filmformed on the second surface, it is possible to suppress the generation of a gap or void in the corner portion between the first surfaceand the second surface.

For example, the first insulating filmmay be uniformly formed on a circular support plateof approximately 30 cm by repeating formation of the first insulating filmon at least a part of the first surfacewhile moving the device sprayerincluded in the thermal sprayer 1 mm in a parallel direction to the first surfaceand the formation of the first insulating filmon at least a part of the second surfacewhile moving the thermal sprayerincluded in the thermal sprayer 1 mm in a parallel direction to the second surface.

Optionally, the first insulating filmmay be formed on at least a part of the third surfacewhile moving the thermal sprayerin a parallel direction to the third surface. By repeatedly moving the thermal sprayerfrom the end of the support platetoward the approximate center of the third surfaceof the support plateand moving the thermal sprayerfrom the approximate center of the support platetoward the end of the support plate, the first insulating filmmay be formed on at least a part of the third surfacewhile moving the thermal sprayerin a zigzag manner. At this time, the first insulating filmmay be uniformly formed on the first surface, the second surface, and the third surfaceof the support plateby repeatedly forming the first insulating filmon at least a part of the first surface, the first insulating filmon at least a part of the second surface, and the first insulating filmon at least a part of the third surface.

1-3. Comparison Between a Corner Portion of Support Plate of a Conventional Stage and a Corner Portion of Support Plateof StageAccording to an Embodiment of the Present Invention

is a cross-sectional view for explaining a part of a corner portion of the support plate of the conventional stage.are cross-sectional views showing a part of the corner portion of the support plateof the stageaccording to an embodiment of the present invention.is an example of images obtained by capturing a part of the corner portion of the support plateof the stageaccording to an embodiment of the present invention. Description of the same or similar components as those ofmay be omitted. In the following explanation, the stagehaving the configuration shown inwill be exemplified.